Exodus 8:20-28

And Jehovah said unto Moses, Rise up early in the morning, and stand before Pharaoh; lo, he cometh forth to the water; and say unto him, Thus saith Jehovah, Let my people go, that they may serve me. Else, if thou wilt not let my people go, behold, I will send swarms of flies upon thee, and upon thy servants, and upon thy people, and into thy houses: and the houses of the Egyptians shall be full of swarms of flies, and also the ground whereon they are. And I will set apart in that day the land of Goshen, in which my people dwell, that no swarms of flies shall be there; to the end thou mayest know that I am Jehovah in the midst of the earth. And I will put a division between my people and thy people: by to-morrow shall this sign be. And Jehovah did so; and there came grievous swarms of flies into the house of Pharaoh, and into his servants’ houses: and in all the land of Egypt the land was corrupted by reason of the swarms of flies. And Pharaoh called for Moses and for Aaron, and said, Go ye, sacrifice to your God in the land. And Moses said, It is not meet so to do; for we shall sacrifice the abomination of the Egyptians to Jehovah our God: lo, shall we sacrifice the abomination of the Egyptians before their eyes, and will they not stone us? We will go three days’ journey into the wilderness, and sacrifice to Jehovah our God, as he shall command us. And Pharaoh said, I will let you go, that ye may sacrifice to Jehovah your God in the wilderness; only ye shall not go very far away: entreat for me.